The research provides converging experimental studies designed to investigate the role of motivational, perceptual, and learning processes in the development of adaptive exploratory behaviors of premature infants during the first year of life. Operant learning procedures are employed to assess the responsiveness of premature infants to different classes of sensory reinforcement and to assess the development of learning and perceptul capacities. The reliability and validity of performance measures on experimental tasks as early measures of individual subject differences, as well as early measures of perceptual and learning deficits as a function of birth status, are examined. Studies on the effects of compensatory stimulation programs are designed to investigate specific changes in motivational and learning processes that may be the result of early exposure to routine programs of hospital care and restricted patterns of stimulation.